Secondary batteries are widely used in electronic devices such as mobile phones, notebook computers and the like due to high energy density and environmental friendliness. In recent years, in response to environmental issues, issues of gasoline price and energy storage, application of secondary batteries has rapidly expanded to hybrid vehicles, electric vehicles, and energy storage systems.
An electrode assembly of a conventional secondary battery includes a main body and a tab connected to the main body. The main body is usually wound as a multi-circle structure, and two tabs are provided in each circle. When the tab of such structure is connected to a connecting piece of the secondary battery after being bent, a misalignment of ends of the tab may be caused by its bending. A degree of misalignment of the tab at the outermost side is the greatest, when compared with the tab at the innermost side. Besides, the thicker the tab is, the greater the degree of misalignment is. If the tab is too short, it may causes that the tab at the outermost side cannot be connected to the connecting piece. If the tab is too long, it may lead to a great redundancy of the tab at the innermost side formed after the bending, which is likely to result in a connection between the tab and other components in the secondary battery and thus causes an internal short-circuit of the secondary battery, thereby further causing an accident.